In 1986, Audi introduced a proprietary Safety Restraint System known as the procon-ten system. This restraint system, whose acronym stood for Programmed Contraction-Tension, utilized high strength cables routed behind and attached to the rear of the engine. These cables were also attached to the steering column and seat-belt mounts.
In the event of an accident, the engine would be pushed towards the firewall, applying tension to the cables. When the cables were pulled taught, the steering wheel was pulled away from the driver, and any slack was removed from the seat-belts.
During this time, Audi primarily used longitudinally mounted engines. This helped to ensure that the restraint system activated during a frontal impact, since the engine was one of the first things struck in a frontal impact. The system proved to be so reliable and cost effective, that Audi was one of the last German automaker to utilize an Airbag system.
Audi continued to use the procon-ten system until the 1995 model year.